From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp38.i.mail.ru (smtp38.i.mail.ru [94.100.177.98]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dev.tarantool.org (Postfix) with ESMTPS id 71B6645C304 for ; Wed, 16 Dec 2020 16:05:35 +0300 (MSK) References: <8178e04ab747795298ad57bc33d0b28392b291fe.1607879643.git.v.shpilevoy@tarantool.org> From: Serge Petrenko Message-ID: <5e5f8b7f-3d48-b59e-627e-05dedc769490@tarantool.org> Date: Wed, 16 Dec 2020 16:05:33 +0300 MIME-Version: 1.0 In-Reply-To: <8178e04ab747795298ad57bc33d0b28392b291fe.1607879643.git.v.shpilevoy@tarantool.org> Content-Type: text/plain; charset="utf-8"; format="flowed" Content-Transfer-Encoding: 8bit Content-Language: en-GB Subject: Re: [Tarantool-patches] [PATCH 5/8] raft: fix crash when received 0 term message List-Id: Tarantool development patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Vladislav Shpilevoy , tarantool-patches@dev.tarantool.org 13.12.2020 20:15, Vladislav Shpilevoy пишет: > Term in raft can never be 0. It starts from 1 and can only grow. > It was assumed it can't be received from other nodes because they > do the same. There was an assertion for that. > > But in raft_msg, used as a transport unit between raft nodes, it > was still possible to send 0 term. It could happen as a result of > a bug, or if someone would try to mimic the protocol but made a > mistake. > > That led to a crash in the assert in debug build. > > Part of #5303 > --- Thanks for  the patch! LGTM. > src/lib/raft/raft.c | 1 - > test/unit/raft.c | 8 +++++++- > test/unit/raft.result | 3 ++- > 3 files changed, 9 insertions(+), 3 deletions(-) > > diff --git a/src/lib/raft/raft.c b/src/lib/raft/raft.c > index 4d07d37e5..df34d81dc 100644 > --- a/src/lib/raft/raft.c > +++ b/src/lib/raft/raft.c > @@ -241,7 +241,6 @@ raft_sm_become_candidate(struct raft *raft); > static const char * > raft_msg_to_string(const struct raft_msg *req) > { > - assert(req->term != 0); > char buf[1024]; > int size = sizeof(buf); > char *pos = buf; > diff --git a/test/unit/raft.c b/test/unit/raft.c > index dfb5f8e43..1ed8b7af7 100644 > --- a/test/unit/raft.c > +++ b/test/unit/raft.c > @@ -247,7 +247,7 @@ raft_test_recovery(void) > static void > raft_test_bad_msg(void) > { > - raft_start_test(6); > + raft_start_test(7); > struct raft_msg msg; > struct raft_node node; > struct vclock vclock; > @@ -280,6 +280,12 @@ raft_test_bad_msg(void) > "candidate without vclock"); > is(node.raft.term, 1, "term from the bad message wasn't used"); > > + msg = (struct raft_msg){ > + .state = RAFT_STATE_FOLLOWER, > + .term = 0, > + }; > + is(raft_node_process_msg(&node, &msg, 2), -1, "term can't be 0"); > + > raft_node_destroy(&node); > raft_finish_test(); > } > diff --git a/test/unit/raft.result b/test/unit/raft.result > index a63515ed3..2398bd71c 100644 > --- a/test/unit/raft.result > +++ b/test/unit/raft.result > @@ -45,13 +45,14 @@ ok 1 - subtests > ok 2 - subtests > *** raft_test_recovery: done *** > *** raft_test_bad_msg *** > - 1..6 > + 1..7 > ok 1 - state can't be 0 > ok 2 - term from the bad message wasn't used > ok 3 - node can't be a candidate but vote for another node > ok 4 - term from the bad message wasn't used > ok 5 - node can't be a candidate without vclock > ok 6 - term from the bad message wasn't used > + ok 7 - term can't be 0 > ok 3 - subtests > *** raft_test_bad_msg: done *** > *** raft_test_vote *** -- Serge Petrenko